{"id":1158,"date":"2023-12-26T14:01:55","date_gmt":"2023-12-26T05:01:55","guid":{"rendered":"https:\/\/yamahachi-chemical.co.jp\/en\/?post_type=works&p=1158"},"modified":"2026-10-15T12:53:22","modified_gmt":"2026-10-15T03:53:22","slug":"columnsflashstamp23","status":"publish","type":"works","link":"https:\/\/yamahachi-chemical.co.jp\/en\/works\/columnsflashstamp23\/","title":{"rendered":"What Is a Pre-Inked (Flash) Stamp? Types and How It Is Made"},"content":{"rendered":"\n

Pre-inked stamps let you stamp again and again without an ink pad.<\/p>\n

This article explains how pre-inked stamps work, the differences between the two types (relief type and flat type), and how each is made, using comparison tables.<\/p>\n\n

What is a pre-inked stamp?<\/h2>\n

A pre-inked stamp is a stamp with ink stored inside the stamp surface (the text part), so you can stamp repeatedly without an ink pad. The ink absorbed inside the stamp surface seeps out little by little each time you press it. Pre-inked stamps made with a flash machine are also called “flash stamps”.<\/p>\n

They are widely used for company stamps, address stamps, date stamps and other jobs where you stamp the same image many times.<\/p>\n\n

The two types of pre-inked stamps<\/h2>\n

There are two types of pre-inked stamps, depending on the structure of the stamp surface: the relief type and the flat type.<\/p>\n\n\n\n\n\n\n\n\n
<\/th>\nRelief type<\/th>\nFlat type<\/th>\n<\/tr>\n
Material<\/td>\nRubber, etc.<\/td>\nPorous plastic<\/td>\n<\/tr>\n
Stamp face<\/td>\nRaised and recessed<\/td>\nFlat, with no raised parts<\/td>\n<\/tr>\n
Fine text and photos<\/td>\nDifficult (spreads when pressed hard)<\/td>\nGood (stays sharp even when pressed hard)<\/td>\n<\/tr>\n
Durability<\/td>\nWears easily; dirt collects in the grooves<\/td>\nHighly resistant to wear; long-lasting<\/td>\n<\/tr>\n
Stamping consistency<\/td>\nThe imprint changes with pressure<\/td>\nConsistent imprints<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The relief type has a traditional structure. Its weak points are that the imprint changes with how hard you press, and dirt collects in the grooves. The flat type uses porous plastic and has no raised parts, so it reproduces fine text, line art and even photos clearly, and stamps consistently.<\/p>\n

\"Flat-surface<\/p>\n\n

How pre-inked stamps are made<\/h2>\n

The two types are made in very different ways.<\/p>\n\n\n\n\n\n
Type<\/th>\nRaw material<\/th>\nSteps to make the stamp face<\/th>\nMachine<\/th>\nMain makers<\/th>\n<\/tr>\n
Relief type<\/td>\nRubber, etc.<\/td>\nMolding \u2192 removing additives \u2192 drying \u2192 ink filling<\/td>\nPress, etc.<\/td>\nStamp manufacturers<\/td>\n<\/tr>\n
Flat type<\/td>\nPorous resin<\/td>\nMaking the stamp face \u2192 ink filling<\/td>\nDesktop flash machine<\/td>\nStamp shops, etc.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

The relief type needs many steps, so it suits mass production and is made by stamp manufacturers. The flat type can be processed at low temperatures. A “flash machine” with a built-in lamp creates the stamp face, so stamp shops and stationery stores can easily make these stamps on site.<\/p>\n

Where the lamp’s light reaches the foam through the design film, the pores on the surface melt and seal. After the foam is filled with ink, ink comes out only through the open pores and not through the sealed areas.<\/p>\n\n

Why is the flat type chosen?<\/h2>\n

The heart of the flat type is porous plastic with fine, interconnected pores.<\/p>\n